iommu: Add debugging infrastructure
Currently, debugging IOMMU issues is done via manual instrumentation of
the code or via low-level techniques like using a JTAG debugger.
Introduce a set of library functions and debugfs files to facilitate
interactive debugging and testing.
This patch introduces the basic infrastructure as well an initial
debugfs for:
- viewing IOMMU attachments (domain->dev mappings created by
iommu_attach_device) and resulting attributes (like the base address
of the page tables)
- basic performance profiling
Example usage:
# cd /sys/kernel/debug/iommu/attachments
# cat b40000.qcom,kgsl-iommu:iommu_kgsl_cb2
Domain: 0xffffffc0cb983f00
PT_BASE_ADDR: virt=0xffffffc057eca000 phys=0x00000000d7eca000
# cd /sys/kernel/debug/iommu/tests
# cat soc:qcom,cam_smmu:msm_cam_smmu_cb1/profiling
size iommu_map iommu_unmap
4K 47 us 909 us
64K 97 us 594 us
2M 1536 us 605 us
12M 8737 us 1193 us
20M 26517 us 1121 us
size iommu_map_sg iommu_unmap
64K 31 us 656 us
2M 885 us 600 us
12M 2674 us 687 us
20M 4352 us 1096 us
Change-Id: I1c301eec6e64688831cad80ffd0380743f7f0df6
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
5 files changed